I have one dropdown list for lastname of contacts in my lightning component which have values like all, deshmukh etc and if I select deshmukh from dropdown it should display contacts whose lastname is deshmukh, if it is jail it should display contact whose lastname is jain like that.

code:-
component:-
<aura:component controller="relatedcontactlist" implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,forceCommunity:availableForAllPageTypes,force:lightningQuickAction" access="global" >
   <aura:attribute name="recordId" type="Id" />
    <aura:attribute name="ContactList" type="Contact[]"/>
    <aura:attribute name="columns" type="List"/>
    
    <aura:handler name="init" value="{!this}" action="{!c.myAction}" />
    <lightning:card iconName="standard:work_capacity_usage" title="Related Contacts">
        <lightning:select name="select1" label="Lastnames" required="true">
        <option value="1">All</option>
        <option value="2">Deshmukh</option>
        <option value="3">Pagar</option>
        <option value="4">Joshi</option>
        <option value="4">Jain</option>
    </lightning:select>
        <aura:if isTrue="{!not(empty(v.ContactList))}">
            <lightning:datatable data="{!v.ContactList }" 
                         columns="{!v.columns }" 
                         keyField="Id"
                         hideCheckboxColumn="true"/>
            <aura:set attribute="else">
                <div Style="text-align : center"> " There are no related contacts " </div>
            </aura:set>
        </aura:if>
    </lightning:card>
</aura:component>

controller:-
({
 myAction : function(component, event, helper) 
     {

 component.set('v.columns', [
            {label: 'First Name', fieldName: 'FirstName', type: 'text' },
            {label: 'Last Name', fieldName: 'LastName', type: 'text' }
         ]);

         var ConList = component.get("c.getRelatedList");
         ConList.setParams
         ({
             recordId: component.get("v.recordId")
         });
        
         ConList.setCallback(this, function(data) 
                           {
                               component.set("v.ContactList", data.getReturnValue());
                           });
         $A.enqueueAction(ConList);
 }
})

apex:-
public class relatedcontactlist {
    @AuraEnabled
    public static list<Contact> getRelatedList(Id recordId)
    {
        List<Contact> Conlist = [Select id, name,firstname,lastname from Contact where AccountId=: recordId ];
        return Conlist;
    }
}


Thanks